EC Nutrition

Background: The gut microbiota has emerged as a key regulator of early neurodevelopment. During the first 1,000 days, host-microbe interactions influence synaptogenesis, myelination, stress-axis calibration, and cognitive and behavioral outcomes.

Objective: To review recent evidence on how early-life nutrition and the gut microbiota affect child neurodevelopment, emphasizing biological mechanisms and clinical implications.

Methods: A narrative review was performed following SANRA and PRISMA 2020 guidelines for non-systematic reviews. Literature from January 2015 to March 2025 was searched in PubMed, Scopus, Web of Science, ScienceDirect, MDPI, Frontiers, and Nature Portfolio. Studies in humans (<5 years) and physiologically relevant animal models examining gut microbiota, microbial metabolites (short-chain fatty acids [SCFAs], tryptophan/indoles), or nutritional determinants of neurodevelopment were included. Twenty-seven studies met the inclusion criteria.

Results: Early microbial colonization is shaped by delivery mode, breastfeeding, antibiotic exposure, and maternal-infant diet. Exclusive breastfeeding promotes Bifidobacterium longum subsp. infantis and SCFA production, while cesarean birth and antibiotic exposure are linked to dysbiosis and increased neurodevelopmental-disorder risk. SCFAs regulate neuronal gene expression via HDAC inhibition and FFAR2/FFAR3 signalling, whereas tryptophan-derived indoles activate AhR and modulate mucosal immunity. Balanced microbiota correlates with better cognitive and language performance. Probiotic and symbiotic interventions yield modest but favorable behavioral and inflammatory outcomes.

Conclusion: The gut microbiota is a determinant of infant neurodevelopment. Nutritional interventions-breastfeeding, microbiota-oriented diets, and prudent antibiotic use-represent feasible preventive strategies. A One Health perspective highlights the integration of nutritional, microbial, and environmental factors in promoting lifelong brain health.

 Keywords: Infant Microbiota; Neurodevelopment; Gut-Brain Axis; Breastfeeding; Nutrition; Probiotics; One Health

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